This invention relates to the treatment of various surfaces so that they may be decorated by a sublimatic transfer printing process. Such printing processes involve, as a first step, full color lithographic printing on paper using so called "dispersal" dyes having the property of subliming or vaporizing to a gas when heated. A second step involves transfering the printed image under heat and, usually, pressure in a transfer press to a substrate formed of material which is receptive to the sublimable ink. The inks are capable of being printed onto the paper by lithographic printing methods using etched gravure press cylinders and standard lithographic paper, so that one can obtain the high quality, four color reproduction achievable by these techniques.
Sublimatic transfer processes have been found to be particularly useful in printing full color reproductions onto polyester fabrics. Excellent color quality and efficient transfer is possible with such fabrics, but poor results are usually obtained on non-textile items such as wood, particle board, plastic sheets, leather, rubber and other organic or natural materials. No transfer at all is feasible on glass fabric, sheet glass, metal surfaces, marble, or other inorganic materials.
The present invention provides a method for sublimatic ink transfer to any of the foregoing substrates, whether organic or inorganic. It proceeds by forming a unitary laminate which comprises, at a minimum, a binder layer containing pigment, and a transparent layer, each formed of hydrophobic synthetic polymer. Sublimable dyestuff is heat-transferred from an auxiliary carrier web to the transparent layer to provide a permanent visible pattern of indicia submerged into an external surface of the transparent layer. The laminated combination of transparent layer and pigmented binder results in an article having the color intensity and depth of a photographic print.
Practice of the present process results in the production of unique unitary laminate structures. In one embodiment, the external surface of fiberglass articles can be permanently decorated. Pigment, preferably white pigment, is incorporated in the polyester resin binder base of such articles, and a clear top layer of alkyd resin, melamine formaldehyde resin, or a combination thereof, is applied to the base. The structure is cured to produce a thermoset heat resistant unitary structure which will not soften or deform under the heat and pressure of the sublimatic transfer process. Sublimable ink can then be transferred directly to the transparent, clear top layer.
In another embodiment, one obtains a decorative article having the color depth and quality of a photographic color transparency. In particular, a sheet of polyethylene terephthalate, or other polyester plastic sheet, can be laminated to a pigment-filled similar sheet. The clear sheet can be decorated by the sublimatic transfer printing process to achieve a flexible structure which can be used to produce a number of utilitarian articles, for example, lamp shades, signs, decorative lighted displays, and other various novelty items. The flexible sheets can be laminated to a support member by using the heat of the sublimatic transfer process.
In a further specific embodiment, a rigid substrate, such as sheet metal, glass, marble, or the like, is treated so that it may be decorated by the sublimatic transfer printing process. Preferably, a primer coat is applied to the rigid substrate followed by a layer of pigmented binder and then a transparent layer is applied. The combination is cured and then subjected to a sublimatic heat transfer process. The sheet stock can be formed to a desired shape prior to or after sublimatic heat transfer.
Other aspects of the present invention will be understandable as the invention is described in more detail hereinafter. Prior art of interest to the present invention includes: Defago U.S. Pat. No. 3,782,896, which discloses various polymeric materials that are susceptible to sublimatic ink transfer; dePlasse U.S. Pat. No. 3,813,218 which discloses various sublimable dyestuffs; and Anzai et al U.S. Pat. No. 3,829,286 which discloses sublimatic transfer to various substrates such as artificial leathers, coating, films, sheets, molded products, metallic plates, wooden plates, and the like.